1. Field of the Invention
The present invention relates to a RJ modular connector, and more particularly to a RJ modular connector having a substrate provided therein to balance electrical couplings between terminals and having at least one grounding terminal to eliminate noises.
2. Description of the Prior Art
A RJ modular connector has been widely used in telecommunication system since it was firstly created. A so-called RJ45 modular connector has been widely used in the network system.
The RJ45 modular connector includes totally eight terminals. Resulted from miniaturization of the computer, all corresponding components, including connectors, have to be reduced for their dimension and size. One of the negative consequences or problems resulted from miniaturization is electrical couplings between terminals. Unless the electrical coupling can be effectively controlled within an accepted level, it is unlikely that the RJ45 modular connector can be used in the high-speed signal transmission.
As mentioned above, there are totally eight terminals within the RJ45 connector. There are two different approaches for configuring terminal pair. In the first approach, terminals 1, 2 configure the 3rd pair, terminals 3, 6 configure the 2nd pair, terminals 4, 5 configure the 1st pair, and terminals 7, 8 configure the 4th pair. In the second approach, terminals 1, 2 configure the 2nd pair, terminals 3, 6 configure the 3rd pair, terminals 4, 5 configure the 1st pair, and terminals 7, 8 configure the 4th pair.
The benefit for selecting two terminals as a differential pair, carrying the same signal but with different phases, is if both terminals are affected by the same amount of noise, these noises can be subtracted when both signals arrive at their destination.
Since those eight terminals are equally spaced, electrical coupling between terminals will surely create some problems, i.e. coupling or cross-talk. For example, if we take terminal 3 into consideration, terminal 3 will naturally be imposed with energy from terminals 2 and 4 which are closer to terminal 3. On the other hand, terminal 6, which carries signal having an inverted phase of the signal carried by terminal 3, will also be imposed with energy from terminals 5 and 7. The energy imposed to terminals 3, 6 from respective terminals 4, 5 can be ultimately eliminated because terminals 4, 5 carry the same, but inverted signals. However, energy imposed to terminals 3, 6 from respective terminals 2 and 7 can not be suitably eliminated because terminals 3, 6 is unlikely to establish couplings between terminals 1, 3 and terminals 6, 8 to balance the couplings between terminals 2, 3 and 6, 7. Accordingly, signals transmitted by terminals 3, 6 carry noises resulted from their adjacent terminals 2, 7.
In order to decrease the unwanted electrical coupling between the (3rd, 4th) and (3rd, 2nd) terminals, and (6th, 5th) and (6th, 7th) terminals, many approaches have been provided, such as creating an electrical coupling between 3rd and 1st terminals to balance the unwanted electrical coupling between the 3rd and 2nd, and creating electrical coupling between 6th and 8th terminals to balance the unwanted electrical coupling between the 6th and 7th terminals.
However, as mentioned above, since those eight terminals are arranged in a common plane, it is impossible to create those balancing electrical couplings, i.e. (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals and it is unlikely to create any electrical channels therebetween to create those positive electrical couplings accordingly.
The Siemon Company, a US company, discloses a solution posted on the Internet. A hard copy thereof is herein attached for reference.
As clearly shown in FIG. 4 of that reference, the 6th and 2nd terminals are arranged in the first layer, the 8th, 5th, 4th, and 1st terminals are arranged in the second layer, and the 7th and 3rd terminals are arranged in the third layer.
The 6th terminal in the first layer has a rectangular loop having its longitudinal sides aligned with terminals 4th and 8th located in the second layer, while the 3rd terminal in the third layer also has a rectangular loop having its longitudinal sides aligned with 5th and 1st terminals located in the second layer.
In addition, the right longitudinal loop side of the 6th terminal further includes a square corresponding to a square formed on the 4th terminal. The left longitudinal loop side of the 3rd terminal also includes a square corresponding to a square formed on the 8th terminal.
All arrangements suggested by Siemon are to increase the couplings between (1st, 3rd), (3rd, 5th), and (4th, 6th), (6th, 8th) terminals thereby reducing electrical couplings of the 3rd and 6th terminals corresponding to their adjacent terminals (2nd, 4th) and (5th, 7th) respectively. By this arrangement, it is assumed that the noises imposed on terminals 3, 6 from respectively terminals 2, 7 can be adequately balanced by couplings between terminals 3, 1, and terminals 6, 8.
However, those three sets of terminals are arranged in three different layers, and an insulative material separates either of two adjacent sets of terminals. This will no doubt increase the complexity of the connector.
In addition, there are eight different shapes and configurations among those eight terminals. Each terminal has its own shape which is different from other, especially to the 3rd and 6th terminals, each including the rectangular loop portion which overlaps corresponding terminals to create wanted electrical couplings. Each loop further forms the square to increase the electrical couplings with corresponding terminals having the square. Even the electrical couplings can be created according to the requirement, those eight different configurations of the terminals will surely increase the difficulty and complexity in production.
On the other hand, it has not provided a grounding plane for grounding protections because the eight terminals are insert molded with the terminal material. When the terminals transmit signals, the crosstalk and the electromagnetic interfere (EMI) often happen. Since there is no grounding plane, the integrity of signals is not ensured.
Hence, an improved RJ modular connector is desired to overcome the disadvantages of the prior art connector.
It is an object of this invention to provide a RJ modular connector, and more particularly to a RJ modular connector having a substrate with conductive traces provided thereon to balance electrical couplings between terminals.
It is another object of this invention to provide a RJ modular connector, and more particularly to a RJ modular connector having a pair of grounding terminals to eliminate noise.
It is yet another object of this invention to provide a RJ modular connector which can be easily manufactured and assembled.
In order to achieve the objects set forth, a RJ modular connector in accordance with the present invention comprises a housing defining a plug receiving section and a terminal insert receiving section. A terminal insert is received in the terminal insert receiving section and includes a plurality of terminals and a pair of grounding terminals beside the plurality of terminals. A substrate provides conductive traces, a plurality of grounding traces, a grounding layer and a pair of ground pads thereon. The terminals are securely mounted onto the substrate. An electrical connection is established between one of the grounding terminals and the grounding traces for reducing the noise through the grounding layer and the ground pad.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.